usr/src/lib/libast/common/tm/tmxmake.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                  David Korn <dgk@research.att.com>                   *
  19 *                   Phong Vo <kpv@research.att.com>                    *
  20 *                                                                      *
  21 ***********************************************************************/
  22 #pragma prototyped
  23 /*
  24  * Glenn Fowler
  25  * AT&T Research
  26  *
  27  * Time_t conversion support
  28  */
  29
  30 #include <tmx.h>
  31
  32 #include "FEATURE/tmlib"
  33
  34 /*
  35  * return Tm_t for t
  36  * time zone and leap seconds accounted for in return value
  37  */
  38
  39 Tm_t*
  40 tmxtm(register Tm_t* tm, Time_t t, Tm_zone_t* zone)
  41 {
  42         register struct tm*     tp;
  43         register Tm_leap_t*     lp;
  44         Time_t                  x;
  45         time_t                  now;
  46         int                     leapsec;
  47         int                     y;
  48         uint32_t                n;
  49         int32_t                 o;
  50 #if TMX_FLOAT
  51         Time_t                  z;
  52         uint32_t                i;
  53 #endif
  54
  55         tmset(tm_info.zone);
  56         leapsec = 0;
  57         if ((tm_info.flags & (TM_ADJUST|TM_LEAP)) == (TM_ADJUST|TM_LEAP) && (n = tmxsec(t)))
  58         {
  59                 for (lp = &tm_data.leap[0]; n < lp->time; lp++);
  60                 if (lp->total)
  61                 {
  62                         if (n == lp->time && (leapsec = (lp->total - (lp+1)->total)) < 0)
  63                                 leapsec = 0;
  64                         t = tmxsns(n - lp->total, tmxnsec(t));
  65                 }
  66         }
  67         x = tmxsec(t);
  68         if (!(tm->tm_zone = zone))
  69         {
  70                 if (tm_info.flags & TM_UTC)
  71                         tm->tm_zone = &tm_data.zone[2];
  72                 else
  73                         tm->tm_zone = tm_info.zone;
  74         }
  75         if ((o = 60 * tm->tm_zone->west) && x > o)
  76         {
  77                 x -= o;
  78                 o = 0;
  79         }
  80 #if TMX_FLOAT
  81         i = x / (24 * 60 * 60);
  82         z = i;
  83         n = x - z * (24 * 60 * 60);
  84         tm->tm_sec = n % 60 + leapsec;
  85         n /= 60;
  86         tm->tm_min = n % 60;
  87         n /= 60;
  88         tm->tm_hour = n % 24;
  89 #define x       i
  90 #else
  91         tm->tm_sec = x % 60 + leapsec;
  92         x /= 60;
  93         tm->tm_min = x % 60;
  94         x /= 60;
  95         tm->tm_hour = x % 24;
  96         x /= 24;
  97 #endif
  98         tm->tm_wday = (x + 4) % 7;
  99         tm->tm_year = (400 * (x + 25202)) / 146097 + 1;
 100         n = tm->tm_year - 1;
 101         x -= n * 365 + n / 4 - n / 100 + (n + (1900 - 1600)) / 400 - (1970 - 1901) * 365 - (1970 - 1901) / 4;
 102         tm->tm_mon = 0;
 103         tm->tm_mday = x + 1;
 104         tm->tm_nsec = tmxnsec(t);
 105         tmfix(tm);
 106         n += 1900;
 107         tm->tm_isdst = 0;
 108         if (tm->tm_zone->daylight)
 109         {
 110                 if ((y = tmequiv(tm) - 1900) == tm->tm_year)
 111                         now = tmxsec(t);
 112                 else
 113                 {
 114                         Tm_t    te;
 115
 116                         te = *tm;
 117                         te.tm_year = y;
 118                         now = tmxsec(tmxtime(&te, tm->tm_zone->west));
 119                 }
 120                 if ((tp = tmlocaltime(&now)) && ((tm->tm_isdst = tp->tm_isdst) || o))
 121                 {
 122                         tm->tm_min -= o / 60 + (tm->tm_isdst ? tm->tm_zone->dst : 0);
 123                         tmfix(tm);
 124                 }
 125         }
 126         return tm;
 127 }
 128
 129 /*
 130  * return Tm_t for t
 131  * time zone and leap seconds accounted for in return value
 132  */
 133
 134 Tm_t*
 135 tmxmake(Time_t t)
 136 {
 137         static Tm_t             ts;
 138
 139         return tmxtm(&ts, t, NiL);
 140 }